Pictures: Nature Yields New Ideas for Energy and Efficiency

Rippling With Energy

Long strands of bull kelp ripple beneath the surface of churning coastal waters, drawing fuel from the sun and, perhaps, pointing out a better way for humanity to capture and use energy.

Seaweed is just one of the innovations of nature from which engineers are drawing inspiration as they seek to design energy systems that are cleaner and more efficient. In plants—the engines of photosynthesis—and in creatures as small as insects and as large as whales, advocates of "biomimicry" are looking for systems that can help humanity better meet the challenge of fueling civilization sustainably.

Biomimicry simply means using designs inspired by nature to solve human problems. The idea is that over 3.8 billion years of evolution, nature itself has solved many of the problems that humanity finds itself grappling with today. Since energy is one of the greatest challenges facing the world, with much of the research aimed at designing systems that would work in greater harmony with the planet, it is not surprising that science would look to nature for answers.

Bull kelp, named for its bullwhip shape, is one of the strongest and most flexible seaweeds in the world and can grow up to 100 feet from its holdfast (similar to roots) on the sea floor to the tips of its leaves. The movement of the kelp's leaves as they photosynthesize sunlight into energy inspired at least one Australian company, which is seeking to commercialize a system that generates energy from the gentle motion of floats bobbing up and down in the waves.

BioWAVE: Capturing Ocean Power

Illustration courtesy BioPower Systems

BioPower Systems of Sydney, Australia, is working toward a $14 million pilot demonstration of its trademarked BioWAVE system off the coast of Port Fairy in the southeastern state of Victoria. Late last year, BioPower received a $5 million ($5.2 million U.S.) award from the Victoria government to help bring the project to fruition.

At 250 kilowatts, the planned pilot would have about a fifth of the capacity of a common commercial wind turbine. But it will be connected to the electric grid, and systems of this size in the past have been large enough to power neighborhoods or large institutional buildings, such as schools. It all depends on how much efficiency the system achieves. The company has spent five years performing multiple tests in tanks at increasing scale before ocean deployment.

BioWAVE's floats are designed to pick up the energy from the ocean's waves, while a flexible "stem" would allow the floats to pivot to catch the most energy. But the inspiration gained from seaweed must be tempered by practicality. Unlike kelp, BioWAVE is designed so its floats would flood with water during big storm surges. The floats would then sink to the seabed to await calmer seas. That's important because ocean-wave devices do not work if the waves are too rough. The costs of the system are reduced because BioWAVE does not require an ironclad grip on the ocean floor.

A New Leaf In Energy Storage

Photograph courtesy Dominick Reuter, MIT

Plants are so fantastic at converting energy into a storable form (by photosynthesizing water with sunlight into sugars) that scientists are striving to figure out a way that humans can mimic this basic process.

Massachusetts Institute of Technology scientist Daniel Nocera's artificial leaf device, seen above with some real leaves, is a step closer to making artificial photosynthesis possible.

Made of a silicon solar cell with catalytic materials bonded to each side, the cell, when placed in water, splits water into oxygen and hydrogen for later use in fuel cells. Unlike previous artificial leaves, Nocera's works in ordinary water and requires no wires or equipment. It is lightweight and portable.

If researchers could develop a simple system to collect and store the gases, each of us could have "personal energy" at our fingertips: The hydrogen and oxygen can be fed into a fuel cell that combines them once again into water while delivering an electric current.

Whale Bumps for Power

Photograph by Jason Edwards, National Geographic

The bumps on a humpback whale's flipper, seen here in a mating ritual, are on the "wrong" side. Physicists are familiar with bumps on the trailing edges of wings or fins, but here they are found on the leading edge.

That led Dr. Frank E. Fish, a biologist at West Chester University of Pennsylvania, to try to design a fan blade that moved air as efficiently as a whale's flippers move the animal through water. The result was WhalePower, a Toronto-based company that designs blades for fans, turbines, and more, inspired by a whale's bumps.

On a whale, the bumps help it move effortlessly through the water at much steeper angles than it would otherwise. A Harvard study found that the angle of attack (the angle between the flipper and the direction of water flow) of a humpback whale flipper can be up to 40 percent steeper than a smooth flipper, giving the whale more control.

Published April 19, 2012

WhalePower: Seeking More Efficient Blades

Photograph courtesy Joe Subirana, WhalePower

WhalePower's product is "the first time, other than in whales and some fossilized fish, that this has been done," said WhalePower Vice President of Operations Stephen Dewar. "Everyone knew" that a blade's leading edge should be smooth to facilitate air flow, but the humpback whale proved everyone wrong.

"I did nature documentaries at one point in my career," Dewar added. "And I asked, 'What are the bumps on humpback whales for?' [The response was] 'Oh, they're just barnacles.' They weren't."

Currently, the technology is appearing in industrial fans for warehouses, where WhalePower fans move 25 percent more air than conventional fans while using 20 percent less energy, but WhalePower hopes to retrofit wind turbines with these bumps to increase energy output by 20 percent and reduce the noise associated with large turbines.

Termite Temperature Control

Photograph by Monica Rua, Alamy

A termite mound is like a miniature city, housing as many as a few hundred thousand termites in its above- and below-ground tunnels. And the insects manage to keep their home at a relatively stable temperature. Why not learn from the insects to keep human buildings just as comfy?

Published April 19, 2012

Eastgate: Energy Efficient, But Greater Savings Possible

Photograph by Ken Wilson-Max, Alamy

The Eastgate complex in Harare, Zimbabwe, which opened in 1996, drew inspiration for its construction from the termite mounds that litter the African nation's rural countryside.

The first building to use passive cooling so fully, the Eastgate building's cooling system cost a tenth of conventional systems and uses 35 percent less energy than similar buildings in Harare. It works by absorbing heat into the walls of the building during the day, then using fans to pump the heat into the interior of the building at night.

But in the 20 years since the Eastgate building was designed, biologists have learned more about how a termite mound works, said biology professor Scott Turner, at the SUNY College of Environmental Science and Forestry in Syracuse, New York.

"The Eastgate center was built upon a model of termite mound function that's been the standard model for about 50 years, and that model is almost entirely incorrect," Turner said. While he concedes that the building is "very effective," studying how termites actually move air around (which is more like the inhale-exhale cycle of a lung than a one-way wind tunnel) could "open up a whole new set of interesting ways of capturing wind to control climate." Concrete walls built with small pores could capture gentle breezes and funnel their energy into buildings' existing ventilation systems, he said.

Published April 19, 2012

Snappers Schooled in Efficient Flow

Photograph by William R. Curtsinger, National Geographic

A school of snappers arranges itself to reduce drag and increase efficiency, much as a flock of geese flies in a "V".

"There's a lot of information in the literature as to what the optimal fish school should look like," said CalTech bioengineering professor John Dabiri. So in order to design a better arrangement of wind turbines, his team looked to fish.

Published April 19, 2012

CalTech: Mimicking Nature, Minimizing Turbulence

Photograph courtesy John O. Dabiri, Caltech

Arranging vertical turbines in a school-of-fish pattern allows them to be placed closer together without the turbines' wakes interfering. "We wanted to achieve something similar [to fish schools], where instead of minimizing energy consumed we wanted to maximize energy generated," said Dabiri, of California Institute of Technology's Center for Bioinspired Engineering. The goal, he said, is to increase the amount of wind energy that can be generated in the same amount of space, and so far, the experiments have produced a stunning ten-fold gain in efficiency.

Because the turbines are vertical and shorter than typical propeller-style turbines, they're also quieter and safer for migratory birds than the typical turbines, Dabiri said.

But as seen in the energy applications of bull kelp and termite mounds, nature doesn't necessarily hold all the answers. A lively debate on the limits of biomimicry was touched off when 13-year-old Aidan Dwyer last year won a Young Naturalist Award from New York's American Museum of Natural History for a bio-inspired array of solar panels: instead of arranging them in rows, he built a "solar tree," with panels arranged like leaves on branches.

Bloggers and scientists took Dwyer to task because, when he measured the effectiveness of the panels, he measured voltage instead of power (a combination of voltage and current). In fact, arranging panels to mimic a tree isn't the most efficient layout, because trees aren't the most efficient collectors of sunlight, said Jan Kleissl, an environmental engineer at University of California, San Diego, in an email. "Trees have to combat weight and wind loading. If trees used a steady, continuous surface that was always oriented perfectly towards the sun, the force of strong winds would topple the tree . . . Evolution has to make great trade-offs in supporting life."

The fact that nature can't always serve as a cheat sheet for humans is the "unpopular yet true story," Kleissl added. "Human 'evolution' left natural evolution in the dust during industrialization."

Still, biomimicry advocates believe that nature offers enough lessons about storing and using energy that civilization needs to try to apply these ideas that have evolved over eons, combining them with the human ingenuity of today.